In the application of blast furnace refractories, there are three kinds of commonly used graphite bricks, namely graphite brick, semi-graphite brick and hot-pressed semi-graphite brick. The following mainly introduces the difference between the three graphite bricks in the forming method and application.

Graphite brick

Synthetic graphite, ie artificial graphite or artificial graphite (a material obtained by graphitizing a carbon material at 2400 to 3000 ° C) as a solidified carbon material, a manufacturing method and a method for producing a carbon refractory material as described above similar. However, the binder in this carbon body has been completely carbonized and then sent to another furnace for high temperature treatment (graphitization). This graphitization process not only changes the structure of the carbon particles, but also changes the binder.

It can be seen that the product is different from the aforementioned products in terms of raw materials, particle size, purity and density. The pores can be filled with another binder, such as carbonization after immersion in tar or bitumen under vacuum, to form a product with less pores (high density).

The manufactured graphite chunks or cylindrical blanks (bricks) are cut and machined to obtain large bricks that meet the size requirements.

Semi-graphite brick

The artificial graphite particles are mixed with a binder (tar-asphalt) and carbonized at 800 to 1400 °C. The final product consists of carbon-bound graphite particles, which are carbon-bonded graphite bricks, so their thermal conductivity is much higher than that of carbon bricks.

Semi-graphite bricks are a relatively porous material, but they can also be used to increase the density of graphite bricks. The manufactured semi-graphite bulk or cylindrical body is then cut and machined to obtain a semi-graphite bulk brick.

Hot pressed semi-graphite brick

The hot-pressed semi-graphite brick is a product made by the formulation design of the semi-graphite brick and the production process of the hot-pressed carbon brick. It therefore has a higher thermal conductivity and less permeability than typical semi-graphite bricks.

According to the main raw material composition, hot-pressed semi-graphite bricks have three different properties to suit various purposes, as follows:

(1) Silica and quartz materials composed of crushed graphite particles and added with a carbonaceous binder and an alkali-resistant corrosion, which are produced by a BP method or a "hot pressing method".

(2) It consists of the same graphite and is added with a binder (same (1)), and SiC is used instead of silica and quartz, and is made by BP method or "hot pressing method".

(3) It consists of graphite particles and carbonaceous binder, without adding SiC, silica and quartz materials, and is made by BP method or "hot pressing method". Compared to conventionally fired semi-graphite bricks, performance is improved due to hot pressing.

Since hot pressing is a special manufacturing method, the finished product has a size of not more than 500 mm × 250 mm × 120 mm.

In addition to the above three types of graphite bricks, semi-graphitized bricks are also common brick types in blast furnace construction. The difference between them and semi-graphite bricks and hot-pressed semi-graphite bricks has been briefly analyzed in previous articles. Requirements can be searched on the website.